The invention relates to a jet pipe arrangement for the propulsion and control of aircraft, featuring a stationary first pipe section on which a second pipe section fitted with a thrust nozzle is located so that it is multi-directionally rotatable.
Jet pipes of the above-noted type are known from DE-OS (German Published Unexamined Applications) 2,248,480 and 1,931,747, for example. In these two cases, the stationary first and the rotatable second pipe section fit into each other by means of pipe convexities to achieve the multi-directional rotation of the engine gas exhaust. Actuating devices for the pipe sections which are equipped with the thrust nozzle are not shown in said cases.
In the two above-noted cases, it is regarded as disadvantageous that quite considerable aerodynamic losses of the engine gas exhaust have to be assumed as a result of the convexities of both pipe sections, which losses include so-called well-known "Carnot's shock losses" of fluid dynamics. In these prior cases the desire for suitable rotatability of the second pipe section equipped with the thrust results requires actuating forces to be introduced each in two points as a result of the cardanic suspension. This calls for comprehensive reinforcements on the spherical wall or jet pipe sections which results in disadvantages with regard to weight. Besides, technical problems are to be expected with regard to the creation of a suitable thrust nozzle actuating system as a result of the two pipe sections fitting into each other by means of the convexities.
A further device for the deflection of the propulsive jet of gas turbine jet engines is known from U.S. Pat. No. 3,776,467, in which the stationary engine jet pipe is followed by two pipe sections, rotatably attached to each other, the plane of the pivot bearing or the sectional plane between these two rotatable pipe sections being inclined relative to the jet pipe longitudinal axis such that the propulsive jet is, for example, either deflectable in the vertical engine or jet pipe longitudinal center plane or is multi-directionally deflectable as a result of simultaneous rotation of the two pipe sections relative to each other by equal angles of rotation or by rotating the two pipe sections by different angles of rotation.
Although the last-mentioned known solution may be suitable for relatively slow rotations of the thrust nozzle or the pipe section equipped with the thrust nozzle, problems arise when relatively fast changes of the direction of the thrust vector are required which would result in relatively high rotational speeds and accelerations of the rotatable pipe section and consequent high drive power requirements. Due to the differential gear and rim gears provided in this known arrangement for the drive of the two pipe sections on the pipe sections, a relatively high manufacturing investment and weight is to be expected.
In another contemplated proposal, the second pipe section is equipped with the thrust nozzle and is connected to the first stationary pipe section via a flexible hose or equivalent by means of a hydraulic, pneumatic or mechanical actuating device for rotating the second pipe section. This actuating device is located on the circumference of the engine at several points and has to traverse differently regulated control paths to achieve thrust vector control. In this proposal the forces caused by the sectioned pressure vessel have to be taken up by the actuating elements which will result in relatively high actuating forces and thus relatively large sized components of this actuating device.
An object of the present invention is to eliminate the disadvantages of known solutions and to create a jet pipe of the aforementioned general type, which enables rapid changes of the thrust vector in a comparatively simple way.
As a solution to this problem it is proposed by the invention that actuating elements are located on the first pipe section which are pivotally connected to the second pipe section in such a way, that the second pipe section is rotatable about either a vertical or a horizontal axis of rotation or simultaneously about both of these two axes.
Particularly preferred embodiments of the invention include various of the following advantageous constructional features:
(a) All angle levers which connect the first and second pipe sections are rotatably located with their respective fulcrums on the first pipe section, all fulcrums being preferably in one plane which intersects the engine or jet pipe longitudinal axis. PA1 (b) Two angle lever fulcrums of a first pair of angle levers are located substantially diametrically opposite to each other on the circumference of the first pipe section in a plane parallel to the vertical axis of rotation of the second pipe section. PA1 (c) Two angle lever fulcrums of a second pair of angle levers located substantially diametrically opposite to each other on the circumference of the first pipe section are in plane parallel to the horizontal axis of rotation of the second pipe section. PA1 (d) The pivotal points at the end of a free leg of each angle lever of the first pair of angle levers are on the vertical axis of rotation of the second pipe section, while the pivotal points at the end of one free leg of each angle lever of the second pair of angle levers are on the horizontal axis of rotation of the second pipe section. PA1 (e) Two annular members, as actuating elements, which can be motor-driven either simultaneously or independently of each other, are rotatably located on the circumference of the first pipe section, the first pair of angle levers being attached to the first annular member via their remaining free ends and the second pair of angle levers being attached to the second annular member via their remaining free ends.
These and further objects, features and advantages of the present invention will become more abvious from the following description when taken in connection with the accompanying drawings which show, for purposes of illustration only, several embodiments in accordance with the present invention.